Method of making a welded trailer tank



Sept. 19, 1961 E. RACKEL METHOD OF MAKING A WELDED TRAILER TANK 3Sheets-Sheet 1 Original Filed Feb. 5, 1956 INVENTOR. 2 /27652 )fircieZFTTJF/Vfy Sept. 19, 1961 E. RACKEL 3,000,340

METHOD OF MAKING A WELDED TRAILER TANK Original Filed Feb. 3, 1956 3sheets-Sheet 2 W i Z -5 ll 30 l I Ex/ 1 f INVENTOR.

297652 FQC/ZeZ BY Sept. 19, 1961 E. RACKEL METHOD OF MAKING A WELDEDTRAILER TANK '5 Sheets-Sheet 3 Original Filed Feb. 3, 1956 INVEN TOR. 57652 %(/?6Z BY v a,

United States Patent 3,000,340 METHOD OF MAKING A WELDED TRAILER TANKErnest Rackel, Fort Wayne, Ind., assignor to Fruehauf Trailer Company,Detroit, Mich., a corporation of Michigan Original application Feb. 3,1956, Ser. No. 563,298. Divided and this application Jan. 5, 1959, Ser.No.

4 Claims. (01. 113-120 This application is a division of my copendingapplication Serial No. 563,298, filed February 3, 1956, now abandoned.

This invention relates to improved tank constructions, and moreparticularly, but not necessarily exclusively, to an improved method ofmaking a vehicular tank trailer.

According to presently accepted practice, tanks of tank trailers aremade up of welded-together shaped steel plates. Usually, construction isstarted by building up the top portion of the tank in an upside downposition and attaching end bulkheads to it to form a large bathtublikevessel. Bailles and intermediate bulkheads are set in the vessel atdesired positions, and finally steel sheets are placed over the assemblyto form the bottom portion of the tank. At this stage the assembly isquite strong and rigid. When the bottom sheets are welded in place, theyare, therefore, rigidly held and are not free to move to relieve theshrinking forces produced by the welding. Unsightly buckles and bulgesalong the sides of the tanks often result from the final welding marringthe appearance of the tank and also weakening it structurally.

Another difliculty with present practice is the extensive use of manualwelding in the fabrication of tanks. Manual Welding is not only moreexpensive than automatic types, but also is apt to be less uniform andmore subject to failure. Manual welding is extensively used, however,because many of the welds on a trailer tank are along curved lines thatvary from tank to tank. The shapes and contours of these tanks are soinfinitely varied that tank manufacturers seldom make a sufi'icientnumber of identical tanks to justify the cost of setting up automaticwelding jigs to lay down welds along the curved lines.

A further problem constantly encountered in tank trailer manufacture isthat of reducing the weight of the trailer without reducing itsstrength.

One object of the instant invention is to improve tank trailerconstruction. Another object is to provide tank vehicles of improvedappearance, strength and uniformity. Another object is to provideimproved methods of making tanks with curved ,wall portions using aminimum of hand welding. 1

These and other objects are accomplished by the instant inventionaccording to which a curved wall tank is made of flat sheets weldedtogether to form flat blanks. These blanks are then bentto desiredshapes and welded together to form a tank enclosure. The pn'ncipal'weldsare all made along straight lines so that automatic welding machinerycan be used to produce uniform Welds and to minimize warping. The majorwelds of the final assembly are made in corners so that the weld metalmounds are concealed and do not mar the appearance of the finished tank.The top and bottom wall sections may be flanged before they areassembled in the tank structure to provide catwalk guard and suspensionsupport rails integral with the tank. Also, many auxiliary parts such asvalves, piping and sumps may be assembled on the blanks before the finalassembly is welded together. Additionally, the top and bottom wallsections can be standardized in width, variations in tank shape andcapacity being accomplished by varying the shape of the sides, thusfacilitating automatic welding of the final assembly.

Patented Sept. 19, 1961 The invention will be described in greaterdetail in connection with the accompanying drawings of which:

FIGURE 1 is a side elevational view of a complete vehicular tank trailerembodying the invention;

FIG. 2 is a plan view of a blank used to form a bottom wall section of atank trailer according to the invention;

FIG. 3 is a perspective view of the blank shown in FIG. 2 after it hasbeen bent into shape;

FIG. 4 is a perspective view of the bent blank shown in FIG. 3 in aninverted position and with auxiliary parts added to it to form acomplete assembly for the bottom wall portion of a tank traileraccording to the' invention;

FIG. 5 is a plan view of a blank used to form a top wall portion of atank trailer according to the invention;

FIG. 6 is a perspective view of the blank shown in FIG. 5 after it hasbeen bent into shape to form the top wall portion of the tank trailer;

FIG. 7 is a plan view of a blank to be used to form the rear portion ofa tank trailer side wall;

FIG. 8 is a plan view of a blank used to form the front or nose portionof a tank trailer side wall;

FIG. 9 is a perspective view of a complete side assembly showing theblanks of FIGS. 7 and 8 after they have been bent to shape and weldedtogether;

FIG. 10 is a perspective view of a partially assembled tank traileraccording to the invention;

FIG. 11 is a perspective view of a partially assembled tank traileraccording to the invention, being the same assembly as shown in FIG. 10but including bulkheads and bafiles;

FIG. 12 is a perspective view of a substantially completed tank traileraccording to the invention after assembly of the bottom wall portionupon the sides.

A preferred embodiment of the present invention is represented by avehicular tank trailer, shown generally in FIG. 1, and made ofwelded-together steel sheets. In order to provide maximum strength inthe finished trailer, the sheets are preferably of high tensile steel,which is commercially available as sheets having a maximum width of onlyabout 66 inches, As shown in FIG. 2, several of such sheets 2, 4 and 6are welded together end-to-end, preferably by submerged arc Welding, toform a relatively large blank 8 for the rear bottom portion of the tank.Since the sheets are flat, automatic welding equipment may be utilizedto form these welds and the individual sheets are free to move afterwelding to relieve strains. Slag is removed from the welds and excessweld metal is ground off to form a flat, smooth blank. The blank is thenrolled to a desired curved shape corresponding to the shape of thecenter portion of the tank bottom and its edges are folded over to formintegral rails 10 and 12 along the length of the blank, as shown in FIG.3. A second section 14, similar to the section 8 but shorter in length,is made in an exactly similar manner to the section 8 to form theforward bottom portion 14 of the tank. The forward portion 14, a bottommid-section 16 and the rear bottom portion 8 are welded together,end-to-end, to complete the bottom tank wall. Auxiliary parts such aswheel mounting brackets 18, piping 20 and the upper coupler assembly,including a mounting plate 22 and kingpin 23, are then attached to thebottom tank wall before it is fitted to the other wall portions of thetank.

Referring now to FIG. 5, three additional sheets of flat high tensilesteel 24, 26 and 28 are welded together to form a flat blank 30 for thetop wall of the tank. The blank 30 may be treated in substantially thesame manner as'the blank 8. It is first scaled and ground to remove slagand excess Weld metal. It is then bent to a desired curvature for thetop wall of the tank and broken J) at its edges to form integral catwalkguard rails 32 and 34.

The side sections of the tank are made from two separate blanks 36 and38, each made up of individual flat sheets welded together in a similarfashion to the blanks 8, 14 and 30, as heretofore described. The blank36 is bent to form the main rear side wall of the tank. The blank 38 isbent to form the nose and throat side walls of the tank and the twoblanks 36 and 38 are welded together along the line 39, as shown in FIG.9, to form a complete side wall section 40. This weld 39 is preferablydone by a portable submerged arc Welding process to provide maximumstrength in the finished tank. A second matching blank 42 is formed inan exactly similar manner to the blank 40 to form the opposite side wall42 of the tank.

The shaped sections are then ready for assembly. The top section 30 isinverted and the two side sections 40 and 42 are placed in position withtheir edges abutting the section 30. The side sections 40 and 42 arethen welded, preferably by automatic submerged arc welding equipment, tothe top section 30 along the lines 44 and 46. These welds, like most ofthe preceding ones, are along straight lines to facilitate the use ofautomatic welding equipment in forming them.

Referring now to FIG. 11, end bulkheads 48 and 50 and internal baflles52 are arc welded in place in the assembly to the top section 30 and thetwo side members 36 and 42. The bottom section, consisting of the threelongitudinal members 8, 14 and 16, is then placed over the partiallycompleted tank and welded in place along the lines 54, again preferablyby automatic submerged arc welding equipment. Finishing gussets 56 arewelded in place in the tapering throat section of the tank, one at eachside, to complete the tank enclosure. Subsequently, the welding of thebulkheads 48 and 50 and the baffles 52 is completed by hand. Wheels 60together with any conventional suspension means and a front jack 62 maythen be attached to the bottom of the tank to complete the assembly.

The catwalk rails 32 and 34 serve three functions. First, they form acatwalk on the top of the trailer for access to manholes, ports andequipment that may be carried thereon. Second, they provide overturnprotection in the event of an accident, and third, but probably mostimportant, they form the structure rail for the compression side of thetank. When the tank is loaded, it is stressed and acts as a structuralbeam with the top portion being under compression and the bottom portionunder tension. The catwalk rails 32 and 34 reinforce the top,compression side of the tank to prevent buckling and excessive bending.The lower flanges and 12 form mounting means for the wheels and otherparts of the trailer carried beneath the tank, such as piping,manifolds, valves and the upper couplers 22 and 23. The.

lower rails 10 and 12 also bear a. major part of the tension stress inthe tank, reinforcing the bottom of the tank against the tensionproduced by its load. a

It will thus be seen that most of the welding in a tank traileraccording to the invention may be done by automatic equipment set up toweld only along straight lines. Further, many of the relatively shortwelds of the type that produce buckling in previous constructions aremade in the fiat before the individual sheet members are rigidlypositioned so that the members are free to move torelieve stressescreated by the welding. Automatic welding of the final shell assembly isfacilitated by standardizing the size and shape of the top and bottomportions of the tanks. Thus, automatic welding equipment may bepermanently set up to assemble tanks of widely varying sizes and shapes,the variations being limited to the side wall portions of the tanks.

Another feature of the invention is the provision of catwalk and bottomrails integral with the tank shell. This construction reduces theover-all weight of the trailer While the invention has been describedwith reference to a tank trailer, such as may be drawn by a conventionaltractor, it will readily be seen that it is also applicable to othertank structures such as, for example, self-propelled tank vehicles. Ingeneral, the practice of the invention is advantageous in themanufacture of all relatively large welded metal tanks that have curvedwall sections.

What is claimed is:

1. Method of making a complete generally cylindrical curved sheet metalwall tank comprising the steps of assembling together relatively smallarea rectangular flat sheets of metal in co-planar relation withadjacent edges in butting engagement, then joining the edges of saidflat sheets by straight line submerged arc welding to form a pluralityof relatively large area flat sheet metal blanks, bending said blanks toform portions of said cylindrical curved wall, and welding said blankstogether with straight line welds to form the completed cylindricalcurved wall whereby the cylindrical tank is formed from a plurality ofsmall flat sheets by straight line welds without having to weld curvededges.

2. Method of making a complete generally cylindrical curved sheet metalwall tank comprising the steps of as sembling together relatively smallarea rectangular flat sheets of metal in co-planar relation withadjacent edges in butting relationship, then joining the edges of saidfiat sheets by straight line submerged arc welding to form a pluralityof relatively large area flat sheet metal blanks, bending said blanks toform portions of said cylindrical curved wall, one of said portionsforming a top wall of said tank, a second one of said portions forming abottom wall of said tank, third and fourth ones of said portions formingseparate side walls of said tank, positioning said side walls inabutting relationship to opposite edges of said top wall, welding saidside wall to said top wall with straight line welds, positioning saidbottom wall in abutting relationship to said side walls, welding saidbottom wall to said side walls with straight line welds, and welding endwalls to the structure thus formed to enclose the ends of the tank.

3. Method of making a complete generally cylindrical curved sheet metalwall tank comprising the steps of assembling together relatively smallarea rectangular flat sheets of metal in co-planar relation withadjacent edges in butting relationship, then joining the edges of saidflat sheets by straight line submerged arc welding to form a pluralityof relatively large area flat sheet metal blanks,

bending said blanks to form portions of said cylindrical curved wall,each one of said portions having two longitudinally extending straightedges, one of said portions forming atop wall of said tank, a second oneof said portions forming a bottom wall of said tank, third and fourthones of said portions forming separate side walls of said tank, bendingmarginal portions of said bottom wall parallel to the longitudinallyextending edges thereof outwardly with respect to the cylindricalcurvature thereof to form flanges thereon, the junctures of said flangeswith the cylindrically curved portion of said bottom wall lying alongthe longitudinally extending straight edges thereof, positioning saidside walls in abutting relationship to opposite longitudinally extendingedges of said top wall, welding said side walls to said top wall withstraight line welds, positioning said bottom wall with the longitudinalstraight edges thereof abutting said side walls and said flangesprojecting outwardly, welding said bottom welding end walls to thestructure thus formed to enclose the ends of the tank.

4. Method of making a complete generally cylindrical curved sheet metalwall tank comprising the steps of assembling together relatively smallarea rectangular flat sheets of metal in co-planar relation withadjacent edges in butting relationship, then joining the edges of saidflat sheets by straight line submerged arc welding to form a pluralityof relatively large area flat sheet metal blanks, bending said blanks toform portions of said cylindrical curved wall, each one of said portionshaving two longitudinally extending straight edges, one of said portionsforming a top wall of said tank, a second one of said portions forming abottom wall of said tank, third and fourth ones of said portions formingseparate side walls of said tank, bending marginal portions of saidbottom Wall parallel to the longitudinally extending edges thereofoutwardly with respect to the cylindrical curvature thereof to formflanges thereon, the junctures of said flanges with the cylindricallycurved portion of said bottom wall 1ying along the longitudinallyextending straight edges thereof, bending marginal portions of said topwall parallel to the longitudinally extending edges thereof outwardlywith respect to the cylindrical curvature thereof to form flangesthereon, the junctures of said last-mentioned flanges with thecylindrically curved portion of said top Wall lying along thelongitudinally extending straight edges thereof, positioning said sideWalls in abutting relationship to opposite longitudinally extendingedges of said top wall, welding said side walls to said top wall withstraight line welds, positioning said bottom wall with the longitudinalstraight edges thereof abutting said side walls and said flangesprojecting outwardly, Welding said bottom wall to said side walls withstraight line welds extending along the longitudinal edges of the bottomwall, and welding end walls to the structure thus formed to enclose theends of the tank.

References Cited in the file of this patent UNITED STATES PATENTS1,798,190 Carter Mar. 31, 1931 1,965,736 Dillman July 10, 1934 2,097,113Bradley Oct. 26, 1937 2,199,737 Bernstein May 7, 1940 2,301,061 LogemanNov. 3, 1942 2,684,528 Rossheir July 27, 1954 FOREIGN PATENTS 736,757Great Britain Sept. 14, 1955

